Ex-Pfizer cancer drug shows mixed results in mid-stage studies

Puma Biotechnology made its debut at the San Antonio Breast Cancer Symposium, presenting some positive data from mid-stage studies of the cancer drug the developer licensed from Pfizer ($PFE). The data support the drug's potential to offer a new way to combat HER2-positive and aggressive breast cancers.

The slate of Phase II data revealed the promise of the ex-Pfizer drug, called PB272 or neratinib, tested in combination with chemotherapy. However, results from a separate mid-stage study of the drug used alone showed it didn't help certain patients live longer without their breast cancer getting worse versus those who got a combo of GlaxoSmithKline's ($GSK) Tykerb (lapatinib) and the chemo drug capecitabine.

In the Phase I/II study involving breast cancer patients previously treated with Roche's Herceptin and chemo, the company said 61 patients who also had not been treated with the HER2 targeted agent lapatinib received PB272 and the chemo drug capecitabine. Results showed 7 (11%) patients experienced a complete response, 32 (52%) patients experienced a partial response and 5 (8%) patients experienced stable disease for greater than 6 --an overall response rate of 64% and a clinical benefit rate of 72%.

As planned, the company aims to move forward with development of the drug in patients with HER2-positive and metastatic breast cancers, CEO Alan Auerbach said. Auerbach was previously chief of Cougar Biotechnology, which Johnson & Johnson ($JNJ) scooped up in a $1 billion deal for the rights to the prostate cancer drug Zytiga.

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